


Two Very Different Sets of Dinner Plans

by Guardian_Rose



Category: Merlin (TV), Shadowhunters (TV)
Genre: Alternate Universe - Canon Divergence, Canon Era, Established Relationship, Fluff, Happy Ending, M/M, Spell mixups, for like some of it, happy everything
Language: English
Status: Completed
Published: 2018-07-19
Updated: 2018-07-19
Packaged: 2019-06-13 02:32:34
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,950
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15354291
Author URL: https://archiveofourown.org/users/Guardian_Rose/pseuds/Guardian_Rose
Summary: He sighed when no reply came and turned around to head back into their room.“You’re not Merlin.”“Astute observation. Honestly, should have realised where I was as soon as I saw the colour scheme. Nice to see you again, Arthur.”****“Tell me where I am first. Where’s Arthur?”“Arthur?”Realisation hit Alec like a brick. “Oh for the love of- you’re Merlin Emrys, aren’t you?”





	Two Very Different Sets of Dinner Plans

**Author's Note:**

> From this wonderful anonymous prompt on tumblr:
> 
> Just a story idea, what if Magnus Bane and Merlin somehow switch places because of a spell and Alec and Arthur are desperately trying to get their love back?

“ _ Mer _ lin, hurry up! We’re going to be late to our own feast!” Arthur dropped his head back against the door to their quarters, glaring at the guard next to him who tried to stifle a laugh. “I will leave without you!” 

  


He sighed when no reply came and turned around to head back into their room. 

  


“You’re not Merlin.”

  


“Astute observation. Honestly, should have realised where I was as soon as I saw the colour scheme. Nice to see you again, Arthur.” 

  


****

  


Alec was exhausted. Bone deep weariness was causing everything to ache. Even his Angel-damned toes were aching and he hadn’t even known that was possible. It probably shouldn’t  _ be _ possible. He dropped his bow onto his desk and slumped into his chair, sighing in relief as he leaned back. Soon enough Magnus would arrive to take him home to have dinner. Maybe he’d ask to put a film on, one that he could fall asleep listening to whilst curled up with Magnus on the sofa. That’d be nice.

  


He smiled to himself, playing the evening out in his head as he took a minute to breathe.

  


“Alec!” 

  


Alec groaned in protest but stood up as fast as his legs would allow and opened the door just as Jace reached him. “What is it now?”

  


“I uh- well, you see, it’s a bit complicated.” Jace’s brows were pulled together, Alec had known his parabatai long enough to know when he was trying to paint a prettier picture than reality presented.

  


“What have you done now, Jace? Do I need to grab a weapon?” 

  


“Woah, what’s with the instant assumption that it’s  _ my _ fault?”

  


“Is it?”

  


“No!” Jace cried, throwing his hands up in the air dramatically before grabbing Alec by the wrist and all but dragging him to the training room.

  


“Jace,” Alec came to a halt in the open doorway and pulled his wrist back, hand paused halfway to the hilt of the dagger strapped to his thigh, “who’s that?”

  


A man, roughly the same height as Magnus with similarly coloured black hair stood against the far wall with Izzy seemingly frozen in place, whip caught mid-air. He wore a brown jacket over a purple shirt, complete with a neckerchief of all things and no shoes; his blue eyes darted over to take in Alec, who was quickly trying to decide how best to diffuse the situation. The man was familiar in a strange way, like Alec had seen him in the streets often but never bothered to introduce himself, but also clearly a warlock, without any obvious warlock mark.

  


“Where am I?” The man asked, golden eyes flicking between the three Lightwood siblings. 

  


Jace threw an arm out, as if to say ‘see-what-I-mean’. “One minute me and Iz are sparring when Magnus waltzes in asking where you are, all normal and then poof, Magnus is gone and this dude is freaking about! Izzy tried to uh...well, you can see how well that went.”

  


Alec nodded, squinting at the stressed Man’s face. There was something familiar about his clothes as well, that combination of colours maybe? He shook his head, it would have to wait. 

  


“Let my sister go and we can talk. Peacefully.” He held his hands up in a show of surrender and took a couple of steps into the room, Jace at his back following Alec’s lead.

  


“Tell me where I am first. Where’s Arthur?” 

  


“Arthur?”

  


Realisation hit Alec like a brick. “Oh for the love of- you’re Merlin Emrys, aren’t you?” Magnus had a couple of photos up around the apartment of himself and Merlin and a blond man Magnus had named as Arthur. “Magnus told me some stories about you, I met Arthur once too. When you were in Magnus’ study working on some spell or something.”

  


He’d walked into their apartment to find a stranger fixing himself a cup of coffee, a second mug filled to the brim with tea next to the kettle. Alec was used to coming home to find Magnus still occupied with clients but normally his boyfriend would give him a bit of warning. Alec had put away his gear before introducing himself. He remembered how he’d been struck by how old his eyes looked compared to the young body and face, those eyes had held centuries of pain and wisdom and  _ life _ . Magnus had poked his head out of the study upon hearing Alec’s voice and beckoned him over for a hello kiss, thoroughly distracting him from asking anymore questions.

  


“You know Arthur? How? Who are you people? I don’t know a Magnus.” Merlin seemed wary still but less like he wanted to freeze them all on the spot.

  


“Alec, you know him?” Jace asked, voice pitched just that little bit higher than normal belying his intimidating facade.

  


“Let our sister go, and we can fix this. Please, Merlin.” 

  


Merlin looked over at Izzy again at last, he looked a bit surprised to see her there still. They watched as he muttered something and his eyes flashed a darker gold before fading to blue. Izzy’s whip dropped to the floor and she stumbled forward a step, swearing a mile a minute in outrage.

  


****

  


“How do you know my name? What have you done with my husband?” Arthur thought about shouting for help, alerting the guard outside, but the man currently standing out like a sore thumb in his maroon jacket and  _ extremely _ tight fitting trousers didn’t seem like much of a threat.

  


He was adorned with more jewellery than he’d seen any man wear and his hair... Arthur assumed it must be magic that had coloured the tips of his hair an almost matching dark red. 

  


“Oh goodie, this is going to be fun to explain.” The man murmured to himself before walking past Arthur to sit  _ on  _ his table. “I- who’s Merlin to you currently, husband did you say?”

  


“What does that matter to you? Tell me who you are and what you’re doing here before I draw my blade.” Arthur dropped his voice low, threatening. 

  


The man rolled his eyes. “My name is Magnus, a pleasure to make your acquaintance, Arthur. Again. I can’t explain why I’m here until you answer my question.”

  


“You do realise I’m your King? I don’t have to answer any question unless I see fit.”

  


“Oh, god. I wish Merlin was here to have heard you say  _ that _ .” Magnus said with a chuckle, seemingly unaware, or at least unconcerned, with how thin Arthur’s patience was starting to run.

  


“I won’t ask again.”

  


“Nice to know you’ve always been a bossy prat. I think, and I can’t say this for certain, that Merlin and I had a little magical mix-up and have managed to swap places.” He waved a hand, complete with what looked like dark blue nails, dismissively. “It’s fine. I’ll figure out how to swap us back in no time, or Merlin will first.”

  


“Let me get this straight. You’re a sorcerer. You mixed up a spell and now Merlin is trapped in some other world?”

  


“Ah, no. No. I know you two in the future, which leads me to believe that this is more of a…time travel incident as well as an issue with having moved in space too. And trust me, my boyfriend is not going to be too happy about this either. We were meant to have dinner. I was going to cook and everything.”

  


“I-...You- What?” Arthur let himself be helped into a chair, a headache was beginning to stop him from even trying to wrap his head round the situation. 

  


“What are you all dressed up for? Had a date with Merlin?”

  


****

  


“Arthur is going to kill me.”

  


Alec frowned at Merlin’s distressed statement, yet again thrown for a loop as the man buried his head in his hands. They had moved to Alec’s office for some better privacy; Izzy stood by the door, prepped to send anyone who came knocking away whilst Jace had been pulled away by Clary. 

  


“Um. I’m sorry about that?”

  


“No, I’m sorry, I know that I should probably start focusing on getting back and getting your…?”

  


“Magnus. My boyfriend.”

  


“Right, getting Magnus back. But I was already running late, I’m not even dressed yet!”

  


“You look pretty dressed to me, sadly.” Izzy commented, throwing a wink his way causing her brother to roll his eyes. 

  


Merlin flushed, coughing loudly before clearing his throat; Alec shot Izzy a reproachful look before offering to fetch their guest a drink.

  


“I’m fine, thanks.” Merlin waved him away. “And um, thanks I think for the uh interest, miss, but I’m already married. Happily. Well, maybe not so happily now I’m so utterly late for my own anniversary.”

  


“Anniversary of what?”

  


“Oh, just my coronation.” 

  


****

  


“Why don’t you just go to your feast or whatever, Arthur. I can’t focus with you flitting about over my shoulder.” Magnus grit his teeth as Arthur sat down again. Then stood up to restart his pacing.

  


“I can’t very well turn up to a celebration for Merlin’s coronation without  _ Merlin _ .”

  


“Isn’t it also your wedding anniversary then?” Magnus asked, giving up on trying to get some peace and quiet. 

  


Arthur froze near the window. “Ah, right. Well, it is as far as the people know.”

  


“Arthur, how long have you  _ lied _ to your kingdom? I never thought you’d have it in you, Merlin definitely but not you with your ridiculously royal responsibilities.” Magnus teased, clicking his fingers together to produce one of the spell books he knew Merlin had kept since his time in Camelot.

  


“We aren’t lying! How dare you-”

  


“Oh you’re threatening now, there’s the Arthur I know.”

  


“Merlin and I are married! We did get married in front of the kingdom this day three years ago. We just, were married by the druids a bit before that.” 

  


“How long before?” Magnus asked, genuinely curious. 

  


“We’ve been married for five years, together for seven. Happy now? How long until you can,” Magnus’ eyebrows rose as Arthur did a very good impression of Alec’s own gesture for his magic, “get Merlin back?”

  


****

  


“How long until you think you can get Magnus back?” 

  


“You’re almost as bad as Arthur! Go talk to your sister or something. Your little glass thing keeps flashing so that’s gotta be important.”

  


****

  


“I can’t cast the spell if you’re standing looking over my shoulder, Arthur.”

  


“Oh, right right. Sorry.”

  


****

  


“Well, it was lovely meeting you, Alec.”

  


Alec shook Merlin’s outstretched hand with a smile. “The same to you, I’ll be sure to ask you about this next time we meet.”

  


“I’m sure I’ll like that. That’s such a weird thing to say.”

  


****

  


“Goodbye Arthur, hope your evening looks up from here.”

  


“Thanks.”

  


Magnus rolled his eyes at Arthur’s crossed arms and skeptical frown and started the spell.

  


****

  


Alec didn’t actually see Merlin disappear or Magnus appear. In the blink of an eye they’d switched. Magnus slumped back against the coffee table, only stopped from sitting on the cluttered table by Alec’s supporting embrace. 

  


“I missed you.” Magnus whispered, curling into Alec’s body without a moment's hesitation. 

  


“We can just order takeaway tonight, I think we’ve done enough to deserve it.” 

  


“You are an actual angel, darling.”

  


“Says you.” Alec said shyly, pulling Magnus into a soft kiss.

  


****

  


“You aren’t even dressed?” Arthur cried, albeit after practically squeezing the life out of Merlin.

  


“What a pleasant reunion this is. Remind me why I came back?” Merlin griped but couldn’t and didn’t try to stop from smiling as he wrapped his arms behind his husband’s neck.

  


“You love me really.” Arthur murmured, pressing soft kisses across Merlin’s cheeks.

  


“Mhmm, maybe.”

**Author's Note:**

> Not Beta-ed, all mistakes my own.
> 
> Thank you for reading! <3
> 
> Comments welcome! Especially prompts! <3
> 
> Come and find me on tumblr @guardian-rose-petal <3


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